General Motors Co. is revving up its charm offensive in Washington amid congressional scrutiny of the automaker’s handling of an ignition-switch defect, turning to a leading law firm lobbying shop for help.

Holland & Knight will advocate for GM on “oversight and legislation pertaining to [the] automobile recall,” according to lobbying registration paperwork the firm filed with Congress on Monday. The company this year has recalled 2.6 million vehicles and tied 13 deaths to the ignition-switch problem, triggering litigation and bringing questions from Capitol Hill.